1. Field of the Invention
The present invention relates to agricultural irrigation systems. More particularly, the invention relates to a method and system for operating the drive motors of an irrigation system to maintain alignment of the irrigation system while minimizing the system's simultaneous or peak power usage.
2. Background
Agricultural irrigation systems such as central pivot irrigation machines are commonly used to irrigate crops. A central pivot irrigation machine typically includes, among other things, a central pivot communicating with a pressurized water supply and a series of spans formed from mobile support towers connected to the central pivot and to one another by truss-type framework sections. The mobile support towers are supported on wheels that are driven by a motor on each tower. A water distribution conduit is supported by the framework sections and a number of sprinkler heads, spray guns, drop nozzles, or other fluid-emitting devices are spaced along the length of the conduit.
The mobile support towers and central pivot must stay in general alignment to prevent damage to the joints between the spans. Most known irrigation systems have mechanical mechanisms for maintaining the alignment of the spans. For example, one such mechanism includes a mechanical linkage at each span joint that operates a micro switch on its respective drive motor to turn the drive motor on and off and thus keep the span in alignment with the next span.